REVOKE - remove table priviledges from users

REVOKE removes the followong priviledges from the specifyed users or roles (user groups):
SELECT - query or retrieve data
INSERT - insert new records into a table
UPDATE - modify existing records in a table
DELETE - delete records from a table
ALL - means all priviledges
When PUBLIC is used, the specifyed priviledges will be removed from all users in the database (depending on the concrete RDMBS, the rights will be removed only from the users or the current database).

Example:

REVOKE UPDATE ON tkunden TO my_user;

Here the user my_user looses the right to modify existing records in the table tkunden.